doWhileAsync, reduceAsync and forEachAsync perform async computations on the elements of on Iterables, waiting for the computation to complete before processing the next element.

StreamBuffer allows for the orderly reading of elements from a stream, such as a socket.

FutureGroup is collection of Futures that signals when all its child futures have completed. Allows adding new Futures as long as it hasn't completed yet. Useful when async tasks can spwn new async tasks and you need to wait for all of them to complete.

FutureStream turns a Future<Stream> into a Stream which emits the same events as the stream returned from the future.

StreamRouter splits a Stream into mulltiple streams based on a set of predicates.

CountdownTimer is a simple countdown timer that fires events in regular increments.

Metronome is a self-correcting alternative to Timer.periodic. It provides a simple, tracking periodic stream of DateTime events with optional anchor time.

Cache is a semi-persistent, asynchronously accessed, mapping of keys to values. Caches are similar to Maps, except that the cache implementation might store values in a remote system, so all operations are asynchronous, and caches might have eviction policies.

min, max, and extent retreive the minimum and maximum elements from an iterable.

GeneratingIterable is an easy way to create lazy iterables that produce elements by calling a function. A common use-case is to traverse properties in an object graph, like the parent relationship in a tree.

InfiniteIterable is a base class for Iterables that throws on operations that require a finite length.

implements and classImplements determine if an instance or ClassMirror, respectively, implement the interface represented by a Type instance. They implement the behavior of is for mirrors, except for generics.

getMemberMirror searches though a ClassMirror and its class hierarchy for a member. This makes up for the fact that ClassMirror.members doesn't contain members from interfaces or superclasses.

Method wraps an InstanceMirror and Symbol to create a callable that invokes a method on the instance. It in effect closurizes a method reflectively.

Clock provides points in time relative to the current point in time, for example: now, 2 days ago, 4 weeks from now, etc. For tesability, use Clock rather than other ways of accessing time, like new DateTime(), so that you can use a fake time function in your tests to control time.

Now is a typedef for functions that return the current time in microseconds, since Clock deals in DateTime which only have millisecond accuracy.

Testing Libraries

FakeAsync enables testing of units which depend upon timers and microtasks. It supports fake advancements of time and the microtask queue, which cause fake timers and microtasks to be processed. A Clock is provided from which to read the current fake time. Faking synchronous or blocking time advancement is also supported.